Explosive device



Oct. 18, 1966 D. l. PARKER ETAL EXPLOS IVE DEVICE Filed Dec. 16, 1965 INVENTOR. DAVID I. PARKER and BY ROBERT W. Buss WWQWW drnfi S United States Patent Oflfice 3,279,374 Patented Oct. 18, 1966 3,279,374 EXPLOSIVE DEVICE David I. Parker and Robert W. Bliss, Champaign, Ill., assignors to The Magnavox Company, Fort Wayne, Ind., a corporation of Delaware Filed Dec. 16, 1963, Ser. No. 331,038 4 Claims. (Cl. 102-81.6)

This invention relates generally to explosives. It relates more particularly to pyrotechnic ordnance devices and means for igniting flammable materials in bombs and grenades and other items which are capable of disintegration upon impacting a hard surface.

Many pyrotechnic devices include frangible containers which can be dropped or thrown and will disintegrate upon impact with the surface which they strike. These containers are filled with flammable material and upon disintegrating they allow the material to spread extensively. Fuzes have been devised to ignite the material to provide the desired incendiary eflect.

One disadvantage of some devices heretofore known is the fact that the fuzes required are limited to employment in a specific type of frangible container or are custom-made for a specific container. Another disadvantage is the :fact that a pyrotechnic device with a built-in fuze may subject the fuze to vapors of flammable materials which can interfere 'with proper operation of the fuze.

A disadvantage of many conventional fuzes is that they do not lend themselves to easy installations on a variety of sizes and shapes of flammable liquid containers. Moreover, in some instances, it is necessary to have the container filled with the flammable fluid at all times that the fuze is installed.

It is therefore a general object of the present invention to provide a general purpose fuze well suited to employment with a wide variety of sizes and shapes of containers of explosives or flammable materials.

A further object is to provide a device which can be easily installed on and removed from the container.

A still further object is to provide a device which cannot be armed unless it is mounted on a container in position for proper employment.

A still further object is to provide a device which will not unintentionally be exposed to the contents of the container.

Described briefly, a typical embodiment of the present invention includes a fuze body having a generally V- shaped face adapted to mounting to a frangible container. The body includes an elongated bore having a spring loaded striker therein. A transverse bore receives a lock pin which projects in front of the striker to prevent the striker from moving in the striker bore.

The fuze body is mounted to a frangible container and is secured thereto by a strap. The strap extends around the frangible container and the fuze body and has a suitable adjustment device whereby the appropriate tension can be applied.

Spring washers are between the body and a portion of the lock pin and tend to move the lock pin away from its striker blocking position. However, a safety wire passes through an elongate bore parallel to the striker bore, and passes through an aperture in the lock pin transverse to the axis of the lock pin. This safety wire prevents the lock pin spring from moving the lock pin away from striker blocking position. The mounting strap also engages the lock pin and can retain the lock pin in striker blocking position even when the safety wire has been removed.

The safety wire has a lug engageable with an edge of a transverse aperture in the lock pin. The lock pin spring washers are effective to move the edge in front of the flange of the lug to prevent the safety wire from being removed if the strap is not in place or is not installed with the proper tension.

A spring loaded rotor is normally located in a safety position within a cavity provided at the front end of the body. It is retained in the safety position by the safety wire. A detonator is provided in the rotor. The rotor is pivotally mounted. Therefore, upon removal of the safety wire, its loading spring will turn it through a limited arc to an arming position wherein it presents the detonator in front of the striker bore in position to be struck by the striker whenever the lock pin is released.

A pyrotechnic charge is provided in chambers communicating with the cavity at the front of the body, and is ignited upon the striking of the detonator by the striker. Means are provided to retain the rotor in the armed position, precluding movement of the rotor from the armed position, once achieved.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is a side elevational view of an assembly of the fuze and frangible container according to a typical embodiment of the present invention.

FIG. 2 is an enlarged fragmentary front view thereof illustarting the fuze, with portions being broken away to show interior details.

FIG. 3 is an enlarged fragmentary side elevational view thereof illustrating the fuze, with portions being broken away to show interior details.

FIG. 4 is a front view of the rotor lock.

FIG. 5 is an edge view of the rotor lock viewed in the direction of the arrows 5-5 in FIG. 4.

Referring to the drawings in detail, and particularly 0 FIG. 1 thereof, there is shown a frangible container 11 which, for purposes of example, may be understood to be a glass cylinder having an axis of symmetry 12. The fuze body 13 is secured thereto by means of the strap 14, the strap having a buckle 16 of the infinite adjustment variety which is well known. It is therefore only necessary to pull the end tab 17 of the strap through the buckle 16 until the proper tension in the strap is obtained, and thereupon the teeth 18 will engage the belt and retain it in position.

The fuze body itself is in two pieces including the main body portion 19 and the cap 21 secured thereto by means of the screws 22. A central bore 23 is provided in the body to receive the striker 24, which is loaded by the spring 26 and has a point 27 at its forward end. A transverse bore 28 is provided and receives the lock pin 29. Lock pin 29 has a lug 31 at its lower end which is disposed in front of the striker to prevent the spring 26 from moving the striker forwardly in the striker bore 23. The lock pin also has a circular flange 32 which is integral therewith and has a strap retaining lug 33 extending up from the upper face of the flange.

The fuze body has a cylindrical outer surface 34 into which there is provided a recess 36 having a flat upper face 37 perpendicular to the axis 38 of the lock pin. A counterbore 39 is provided in the surface 37 and is also concentric with the lock pin axis 38. An O-ring seal 41 provides a seal between the fuze body and that portion of the lock pin which is received in the bore 28. This is the central portion of the lock pin and has a transverse aperture 42 therein which passes through the axis 38 in the lock pin. The axis of the aperture 42 is co-planar with the axis 38 of the lock pin and the axis 25 of the striker bore.

A second longitudinal bore 43 is provided in the body 19 and extends through the cap 21. The portion in the cap has a counterbore 44 therein, and is provided with an O-ring seal 46. A safety pin or Wire 47 is received in bore 43 and has a necked down portion 48 passing through the aperture 42 in the lock pin. This provides a shoulder 49 between the necked down portion and the forward end portion 51 of the safety wire. The purpose of this shoulder will become apparent .as the description proceeds. The front end of the safety wire is bent in the shape of an L, which provides a handle portion 52 facilitating withdrawal of the wire, though other configurations may also be found desirable.

A rotor 53 is provided and is pivotally mounted in the cap for rotation about an axis 54 parallel to the axes of the safety wire bore and striker bore. The rotor has a percussion or stab type detonator 56 disposed in the portion opposite the pivot axis. Upon rotation of the rotor from its safe position shown in FIG. 2 to the armed position shown by the dotted outlines, the detonator will be placed directly in line with the axis of the striker bore. The detonator is then exposed to the striker pin in this position. However, prior to removal of the safety wire, the safety wire engages the curved edge 57 of the rotor and prevents its moving from the safe position shown in the solid outline to the armed position shown in the dotted outline. A spring bias on the rotor to move it from safe to armed position is established by the spring 58 wound around the rotor shaft 59 and having one end engaging the inner wall 61 of the cap cavity 62, and having the other end engaging and edge 63 of the rotor. The rear face of the rotor is rounded at its junction with the curved surface 57 to prevent the rotor from impeding withdrawal of the safety wire.

A cavity 64 is provided in the body and has a pyrotechnic mixture or igniter charge 66 therein. The front end of this cavity communicates with the cavity 62 in the end cap 21.

As can be seen in FIG. 3 of the drawing, the lower marginal edge of the aperture 42 in the central portion of the lock pin is engaging the underside of the necked down portion 48 of the safety pin. Under these circumstances, the edge 67 of the lock pin engages the shoulder 49 of the safety wire to prevent removal of the safety wire. In order to maintain this position, two spring washers, 68 and 69 are placed back to back. Each of these washers has lugs providing the spring action. For example, washer 69 has the lugs 71 engaging the upper face 37 of the counterbore provided in the cylindrical outer surface 34 of the fuze body. Likewise, washer 68 has the spring lugs or tabs 72 engaging the fiat washer 75. The inner portion of the upper face of the flat washer 75 engages the underside of the flange 32 on the lock pin. The spring washers are in compression and tend to move the lock pin out of the bore 28 in the fuze body. When there is no strap on the fuze body, the only thing preventing the lock pin from being moved out of position is the engagement of the inner wall of the aperture 42 with the outer portion of the necked down portion 48 of the safety wire. When this occurs, however, the safety wire cannot be pulled out because of the interference between the shoulder 49 and the edge 67 of the lock pin. This is a safety feature to prevent removal of the safety wire when the fuze is not mounted to the container or is not ready for use.

Operation In the operation of the present invention, the fuze is secured to the side of the frangible container, such as the glass jar 11, of FIG. 1. In order to secure it to the container, the strap 14 is used, which has an aperture 73 thereof to receive the aligning lug 33 of the lock pin. A conventional push nut 35 is installed on lug 33 to retain the strap thereon, the teeth 35a of the nut engaging the lug 33. The strap is tightened by pulling tab 17 through the buckle 16 until it is pulled sufficiently to overcome the axial force produced by the spring washers 68 and 69. For a typical example, these spring washers exert a 9-pound force in the direction of the axis 38. Therefore the strap 14 must be tightened sufiiciently to overcome this. When the strap has been tightened to this extent, it can be tightened just a little more and the lock pin will then move in toward the bore 23 and perfectly align the aperture 42 therein with the safety wire 47. The safety wire can then be withdrawn easily by merely pulling it out.

With the safety wire withdrawn, the rotor is enabled to snap into the position shown by the dotted outline in FIG. 2, whereupon it presents the detonator 56 in line with the striker 24. Under these circumstances, it is only the strap holding the lock pin against the load of the spring washers 68 and 69 which prevents the lock pin from being moved out of the position shown. If the tension on the strap is suddenly released, as would occur, for example, if the frangible container is broken, the spring washers 68 and 69 move the lock pin lug 31 out of the path of the striker 24, permitting the striker to move to the front of its bore under the load of the spring 26, whereupon the pin 27 strikes the detonator, which, in turn, sets off the igniter.

Assuming that the frangible container contained gasoline or some other flammable material, the striking of the detonator, coupled with the ignition of the igniter, causes the igniter to ignite the gasoline or other flammable material, whereupon the desired incendiary effects are achieved.

Clearly this fuze can be employed in any instance where a frangible container is intended to be used. It can be used for incendiary bombs or for incendiary grenades. The principles incorporated therein can also be employed for other types of armaments, and are not strictly limited to the incendiary types.

It will be recognized that upon striking a surface after being thrown or dropped, the frangible container and the fuze, or both, are jarred to some extent. In order to prevent any such jarring from moving the rotor out of armed position, a lock is provided to lock the rotor in armed position once it has been moved to that position by the arming spring when the safety wire has been withdrawn.

An example of a rotor lock is the thin beryllium copper stamping 82 disposed behind the rotor and having an aperture 83 receiving the rotor shaft 59. The lock is shaped and sized so that its lateral marginal edges 84 and 86 are parallel to and immediately adjacent the walls 61 and 65 respectively of the cavity. Therefore the lock cannot rotate in the cavity. The lock has a tab 87 there which lies in a plane at an angle with the plane of the major portion of the rotor lock. The angle is designated by reference numeral 88 in FIG. 5. However, when the lock is assembled it is flattened as shown in FIG. 3, thereby creating a restoring force therein tending to return it to the condition shown in FIG. 5.

When the safety wire is removed, allowing the rotor to move to armed position, the rotor is no longer in the way of the rotor lock tab and the tab springs forwardly whereupon the edge 89 thereof moves into position facing the surface 91 of the rotor. When in this position, the edge 89 is buttingly engageable with the surface 91 of the rotor and prevents movement of the rotor from the armed condition even when the fuze is subjected to impact.

A non-slip coating is applied to the V-shaped surface 92 of the body to prevent it from slipping on the surface of the frangible container. Various known coatings can be used.

From the foregoing description, it can be readily recognized that the present invention provides a simple and yet very effective device for achieving the objects and advantages set forth hereinabove. Naturally, it will provide other advantages and benefits which will become apparent to those skilled in the art. a

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art, and within the broad scope of the invention, reference being had to the appendedclaims.

The invention claimed is:

1. An explosive device comprising a body having a rotor pivotally mounted thereto; a striker in said body biased to move into contact with said rotor in one position of said rotor; a detonator in said rotor positioned for engagement by said striker when said rotor is in said one position thereof; a lock member in said body and having a first position interfering with movement of said striker; a safety member disposed in said body and en gaging said lock member to retain it in said first position, said safety member being removable from engagement with said lock member to arm. said device; resilient means biasing said lock member in a direction tending to move said lock member away from said first position to disengage said lock member from said striker; and a tensile member engaging said lock member and opposing the bias of said resilient means after removal of said safety member from engagement with said lock member to retain said lock member in a position restraining said striker.

2. An explosive device comprising: a frangible container; a fuze member having a body with a pair of adjoining surfaces meeting at an obtuse angle, said surfaces engaging the outer surface of said frangible container; a striker member in said body and resiliently biased; a lock member in said body and having a first position engaging said striker and preventing motion of said striker in response to said bias; resilient means engaging said body and said locking member and biasing said locking member in a direction to move said locking member away from said first position; and a strap extending around said fuze and engaging said locking member and extending around said container and securing said fuze body to said container, said strap opposing the locking member biasing means to retain said locking member in striker impeding position until said frangible container is broken to unload said strap.

3. An explosive device comprising: a fuze body; a detonator carrying member in said body movably mounted therein to move from a safety position to an armed position; a striker in said body and movable to a position engaging said detonator carrying member when said detonator member is in an armed position; a locking member impeding movement of said striker member, said locking member being movable between first and second positions impeding said striker member, and said locking member being movable from said first and second position to a third position releasing said striker member; biasing means acting on said locking member in a direction tending to move said locking member from said first position to said second position and from said second position to said third position; a safety member engaging said locking member to prevent movement of said locking member to said third position, said safety member and said locking member having interfering shoulder and wall means thereon preventing disengagement of said safety member from said locking member when said locking member is maintained in said second position by said biasing means, and a restraining member engaging said locking member and opposing the force of said biasing means, said restraining member exerting a force sufficient to move said locking member from said second position to said first position against the urging of said biasing means to normally retain said locking member in said first position, said safety member being disengageable from said locking member when said locking member is in said first position.

4. A fuse comprising: a body having a :rotor pivotally mounted therein, said rotor bearing a detonator, said rotor being biased for pivotal movement from a safety position to an arming position; a bore in said body; a striker disposed in said bore and resiliently biased in a direction to engage said detonator when said rotor is pivoted to said arming condition; a second bore in said body transverse to said first bore; a locking member disposed in said second bore and having a projection entering said first bore and engaging said striker member and impeding motion of said striker member, said locking member having a principal axis colinear with the axis of said transverse bore and said locking member having a transverse aperture therein; a second bore in said body parallel to said first bore; a safety wire disposed in said second bore and extending through said transverse aperture in said locking member, said safety wire having a necked-down portion passing through the said aperture in said locking member and having a shoulder between said necked-down portion and an inner end of said safety wire; spring washer means engaging said body and engaging said locking member and applying a force to said locking member in a direction to move said locking member axially in said transverse bore, said spring means positioning said locking member in a position of engagement between said necked-down portion and a wall of said aperture in said locking member to establish an interference condition between said shoulder of said safety wire and a surface of said lock-ing member, to prevent removal of said safety wire, said locking member remaining in position simultaneously to inhibit movement of said striking member, and said safety wire being in position engaging said rotor and retaining said rotor in safety position.

References Cited by the Examiner UNITED STATES PATENTS 2,397,510 4/1946 Samann 102-70 X 2,426,171 8/1947 Alverson 10281.6 2,960,037 11/1960 Raech et a1 10276 2,969,737 1/1961 Bild 102--70 3,048,111 8/1962 Baker et al. 102-81 X 3,062,142 11/1962 Breza et al. 102-23 3,151,557 10/1964 Evanoif et a1. 102-70 FOREIGN PATENTS 548,304 10/ 1942 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner. G. H. GLANZMAN, Assistant Examiner. 

1. AN EXPLOSIVE DEVICE COMPRISING A BODY HAVING A ROTOR PIVOTALLY MOUNTED THERETO; A STRIKER IN SAID BODY BIASED TO MOVE INTO CONTACT WITH SAID ROTOR IN ONE POSITION OF SAID ROTOR; A DETONATOR IN SAID ROTOR POSITIONED FOR ENGAGEMENT BY SAID STRIKER WHEN SAID ROTOR IS IN SAID ONE POSITION THEREOF; A LOCK MEMBER IN SAID BODY AND HAVING A FIRST POSITION INTERFERRING WITH MOVEMENT OF SAID STRIKER; A SAFETY MEMBER DISPOSED IN SAID BODY AND ENGAGING SAID LOCK MEMBER TO RETAIN IT IN SAID FIRST POSITION, SAID SAFETY MEMBER BEING REMOVABLE FROM ENGAGEMENT WITH SAID LOCK MEMBER IN A DIRECTION TENDING TO MOVE BIASING SAID LOCK MEMBER IN A DIRECTION TENDING TO MOVE SAID LOCK MEMBER AWAY FROM SAID FIRST POSITION TO DISENGAGE SAID LOCK MEMBER FROM SAID STRIKER; AND A TENSILE MEMBER ENGAGING SAID LOCK MEMBER AND OPPOSING THE BIAS OF SAID RESILIENT MEANS AFTER REMOVAL OF SAID SAFETY MEMBER FROM ENGAGEMENT WITH SAID LOCK MEMBER TO RETAIN SAID LOCK MEMBER IN A POSITION RETAINING SAID STRIKER. 